let str: string = "jimmy";
let num: number = 24;
let bool: boolean = false;
let u: undefined = undefined;
let n: null = null;
let obj: object = {x: 1};
let big: bigint = 100n;
let sym: symbol = Symbol("me");

// 执行命令  ts-node basicType.ts
console.log('basic type: ', str, num, bool, u, n, obj, big, sym)